The present invention relates to a device for locking/unlocking the movement of a mobile notched member such as a notched bar mobile in translation or a pinion mobile in rotation.
It is known to effect control of locking and unlocking of a rack or of a pinion by means of a pawl which is constituted by an articulated lever urged by a spring and which bears, at its end, a hook engaging in the troughs between the teeth of a rack or of a pinion. Such a locking/unlocking device presents the drawback of requiring the use of a spring for return of the pawl, which spring is often a cause of breakdown further to breakage or corrosion.
The present invention essentially aims at overcoming this drawback by providing a locking/unlocking device having no return spring and being of particularly simple design.
To that end, this device for locking/unlocking the movement of a mobile notched member, particularly a notched bar mobile in translation or a pinion mobile in rotation, is noteworthy in that it comprises a toothed wheel in mesh, in a zone of contact, with the notches of the mobile member, having a coaxial bore and of which the teeth have a pitch equal to that of the teeth of the mobile member, and a fixed support shaft about which the toothed wheel is mounted to rotate, this fixed support shaft having an outer diameter smaller than the inner diameter of the bore of the wheel such that, subsequent to the radial clearance thus formed, the wheel may move radially between a substantially centered position of unlocking in which the tops of the teeth of the notched mobile member which are the closest to the wheel, are located outside the pitch circle of the teeth of the wheel and the notched mobile member may in that case move freely, and an off-centre position of locking, when the notched mobile member exerts on the toothed wheel a force directed towards the axis of the fixed support shaft, position in which the top of a tooth of the notched mobile member is located, between two teeth of the toothed wheel, within the pitch circle of the teeth of the wheel, such that the notched mobile member and the toothed wheel are locked mutually.